Stamping machine for slotting core plates

ABSTRACT

A stamping machine for slotting annular segment-shaped plates has a movable carriage to which the plate to be slotted is clamped, an arcuate template in engagement with the carriage for guiding the latter in a circularly arcuate path, at least two stepping motors and a drive spindle having a driven side coupled to the stepping motors and a driving side coupled to the carriage, whereby the carriage is displaced in response to the drive spindle movements effected by the stepping motors.

United States Patent Reihle et al.

[ June 24, 1975 STAMPING MACHINE FOR SLOTTING CORE PLATES Inventors: Markus Reihle, Weingarten; Erich Harsch, Baindt, both of Germany Maschinenfabrik Weingarten AG, Weingarten, Germany Filed: Sept. 4, 1974 Appl. No.: 503,160

Assignee:

Foreign Application Priority Data Sept. 5, 1973 Germany 2344697 US. Cl. 83/71; 83/251; 83/267; 83/411 R; 83/412; 269/57 Int. Cl. B26D 7/06 Field of Search 83/71, 251, 411 R, 410, 83/267, 412; 269/57, 56; 72/417; 408/71 References Cited UNITED STATES PATENTS 2/1908 Smith 83/251 X 951,169 3/1910 Worton 83/251 2,433,l 17 12/ l 947 Hallander 3,459,079 8/1969 DeGain 83/411 R X Primary Examiner-Frank T. Yost Attorney, Agent, or FirmSpencer & Kaye [5 7] ABSTRACT A stamping machine for slotting annular segmentshaped plates has a movable carriage to which the plate to be slotted is clamped, an arcuate template in engagement with the carriage for guiding the latter in a circularly arcuate path, at least two stepping motors and a drive spindle having a driven side coupled to the stepping motors and a driving side coupled to the carriage, whereby the carriage is displaced in response to the drive spindle movements effected by the stepping motors.

20 Claims, 7 Drawing Figures PATENTEDJUN 24 ms SHEI SHEET PATENTEDJUN 24 1975 Pmmmum m; A

sum 3 PROGRAMMER PATENTEDJUN 24 I975 v SHE STAMPING MACHINE FOR SLOTTING CORE PLATES BACKGROUND OF THE INVENTION This invention relates to a stamping machine for providing slots in large-diameter core plates formed of annular segments. The stamping machine is of the type having a carriage which supports the core plate segments and which is movable stepwise along a curved template.

Core plates (laminae) for rotary electric machinery are generally manufactured on automatically operating stamping machines which have rotatable and adjustable clamping tables for accommodating core plates of different diameters. In known stamping machines of this type the clamping table executes, for every stroke of the ram that carries the stamping die, a rotary step corresponding to the required slot spacing (pitch) in the core plate.

Core plates of large dimensions are, particularly for the purpose of saving material, formed of annular segments rather than constituting a single-piece annulus. In case of very large dimensions, however, it is difficult to slot these annular core plate segments with known automatic stamping machines if the largest possible distance of the rotary axis of the clamping table from the die tool is smaller than the radius of the core plate segment to be slotted.

It is, to be sure, possible to build a stamping machine with a large clamping table, but even such a solution encounters limits when the diameter of the core plates amounts to several meters.

In a known stamping machine, as disclosed for example in German Accepted Published Patent Application (Auslegeschrift) No. l,627,227, it was proposed to so design the stepwise rotatable clamping table that it is capable of executing superposed displacements (shifts) in two intersecting directions that are perpendicular to the rotary axis of the clamping table. For effecting such displacement in the two directions, there are provided separate drive mechanisms which are activated as a function of the ram stroke cycle. The two drive mechanisms are formed as steplessly and finely adjustable hydraulic or pneumatic systems, while the drive mechanism for rotating the clamping table is constituted by a stepping mechanism driven by the stamping machine.

With a stamping machine outlined in the preceding paragraph it has been expected to slot core plate segments in a very satisfactory manner, since subsequently to each ram stroke (that is, subsequently to the provision of each slot), the core plate segments are rotated about the axis of the clamping table only through an angle which corresponds to the slot pitch, while the clamping table simultaneously is shifted by an always constant distance in two mutually perpendicular directions.

Since during each slotting step, however, the rotary axis of the clamping table has to lie on a circle about the center of the core plate segment, which requirement, in case of a shift of the clamping table by constant distances cannot be complied with, the slot spacing (pitch) in the core plate segments cut by a stamping machine of the above type is only very inaccurate. For this reason the above-outlined stamping machine can find application only in case of core plates which have relatively few slots.

In order to avoid the above-discussed disadvantages, it has been proposed to improve the stamping machine of the type disclosed in the above-mentioned German Accepted Published Patent Application, by providing separate, electronically controlled stepping motors, preferably with hydraulic torque amplification, for the displacement of the clamping table in the one and in the other direction. A stamping machine equipped in this manner is advantageous in that core plate segments of desired dimensions and desired number of slots may be manufactured, since the rotary axis of the clamping table can be moved with great accuracy to come to a rest on a circle about the rotary axis of the core plate segment to assume terminal positions where the stamping proper takes place (the rotary axis of the core plate segment lies externally of the rotary axis of the clamping table). This occurrence is made possible by the arrangement, according to which the number of steps, which vary from slot to slot, are fed to the stepping motors by a program device, for example by a digital preselector switch. It is, of course, feasible to use other types of program processes to control the stepping motors, such as, for example, a circular path control wherein the axis of the clamping table comes to a rest, point-by-point, on a circular are having a predetermined radius. In this type of control it is merely the data regarding the radius and the required number of points that are fed to the stepping motors.

Further, there is known a stamping machine in which the core plate segments are fastened to a carriage which is displaceable along a stationary arcuate template. This template ensures a curved feed path. For a stepwise shift the carriage is provided with a toothed segment (toothed rack) which cooperates with a pawltype driving mechanism or a drive pinion. The drive pinion, in turn, is driven by means of a Ferguson-drive with the interconnection of a change-speed gearing. A disadvantage of this arrangement resides not only in the fact that for each slot pitch a different change-speed gearing is necessary but also that the manufacture of curved toothed racks or pawl rods is very complex and thus inaccuracies may occur.

SUMMARY OF THE INVENTION It is an object of the invention to provide an improved stamping machine from which the abovediscussed disadvantages are eliminated and which, while working with a curved template, is substantially simplified in structure and can be more accurately set.

This object and others to become apparent as the specification progresses are accomplished by the invention, according to which, briefly stated, for the dis placement of the carriage there is provided a drive spindle which is operatively connected with at least two electronically controlled stepping motors each executing sufficiently small and predetermined individual steps.

It is an important feature of the invention that the two stepping motors have differing capabilities of resolution, that is, the one and the other stepping motors cause, per step, displacements of different magnitudes of the carriage. Expediently, the first stepping motor, for the purpose of generating a rotary motion of the drive spindle, is connected with the latter in a direct, mechanical manner, whereas the drive spindle is operatively connected with the second stepping motor in such a manner that, by interconnecting a drive element which converts the rotary motion of the second stepping motor into a longitudinal motion, the drive spindle is axially displaceable in addition to its rotary motion.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic front elevational view of a preferred embodiment of the invention.

FIG. 2 is a schematic side elcvational view of the same embodiment.

FIG. 3 is a schematic top plan view of the same embodiment, carrying a rotor core plate segment.

FIG. 4 is a sectional view of some of the components of the same embodiment taken along line A-B of FIG. 3.

FIG. 5 is a sectional view taken along line CD of FIG. 3.

FIG. 6 is a schematic top plan view of the same embodiment, carrying a stator core plate segment.

FIG. 7 is a sectional view of some of the components of the same embodiment taken along line EF of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to FIGS. 1 and 2, the stamping machine schematically illustrated therein has a clamping table 1 which is displaceable on guide rails 2 towards and away from a die tool (not shown) attached to a reciprocating ram 3. For displacing the clamping table 1 there is provided, for example, a conventional threaded spindle 4 connected to a hand wheel 5.

As it may be observed in FIG. 3, to the clamping table 1 there is secured an arcuate template 6 which has a center of curvature 6a and which serves as a guide for a carriage 7 mounted on the template 6 in a displaceable manner.

The carriage 7 is, for the purpose of reducing friction, provided with guide rollers 8 and 9 which engage, respectively, the lateral arcuate faces 6b and 6c of the template 6. In order to ensure a highly satisfactory guidance of the carriage 7, two guide rollers on each side of the template 6 suffice. The two guide rollers 9 at the inner face 6c of the template 6 are, in a manner known by itself, supported each on a pin 10 which is eccentric with respect to the rotary axis of the associated roller 9. By rotating pins 10, the guide rollers 9 at the face 60 of the template 6 may be adjusted to achieve a clearance-free, biased engagement of the rollers with the template 6.

The carriage 7, as illustrated in FIGS. 3 and 4, has a support 11 comprising a clamping device 12 for the core plate segment 13 which may be, for example, a rotor core segment having a center 13a.

For moving the carriage 7 along the circularly arcuate template 6 there is provided a drive spindle 14 which may be formed as a ball-circulating spindle and which may be, at its driving side, threaded into a ballcirculating nut 15. The latter is, by means of a pin not shown, coupled to the carriage 7 in such a manner that the ball-circulating nut 15 is pivotable in a horizontal plane about an axis 16 which is perpendicular to the thread axis 15a (and thus the axis of the drive spindle 14). The nut 15 is, however, prevented from rotating about the spindle axis relative to the carriage 7. The spindle-andnut assembly 14, 15 may be regarded as a worm-and-screw arrangement wherein a rotation of the component 14 about its longitudinal axis causes a translational movement of the component 15.

In the zone of its driven side, the drive spindle 14, as illustrated in FIG. 5,journals in a setting socket 17. For the purpose of axially immobilizing the drive spindle 14 with respect to the socket 17, the socket 17 and the drive spindle 14 are clamped together by means of a coupling 18 through an axial bearing 19 and an annular collar 14a forming part of the spindle 14. The setting socket 17 is, by means of a clearance-free thread 170, axially movable by rotation in and with respect to a bearing sleeve 20 provided with a complemental inner thread 20a. The bearing sleeve 20 is fixedly secured to a bearing plate 21. The latter is pivotal about the axis 22a of two aligned stub shafts 22 which, in turn, journal in two parallelspaced bearing plates 23 affixed to the clamping table 1.

The drive spindle 14 is driven by a first stepping motor 24, the drive shaft 25 of which is directly connected with the drive spindle 14 by the coupling 18 to effect a direct torque transmission from the drive shaft 25 to the drive spindle 14. For taking up the reaction torque, the stepping motor 24 is affixed to a support plate 26 from which there projects at least one bolt 27 which, in turn, extends in a clearance-free manner into a bore provided in the bearing plate 21. Since the support plate 26, as it will be explained in more detail later, should be capable of executing a certain longitudinal displacement together with the stepping motor 24 secured thereto, the bolt 27 is guided in the bearing plate 21 by means of a ball guide 28.

Beneath the stepping motor 24 there is secured, to the support plate 26, a second stepping motor 29, the drive shaft of which carries a pinion 30 ,which meshes with a ring gear 17b attached to and situated externally of the setting socket 17.

FIGS. 6 and 7 differ from FIGS. 3 and 4, respectively, merely in that the core plate segment rather clamped on the support 11 is a stator, rahter than a rotor core plate segment.

In the description that follows the mode of operation of the stamping machine designed according to the invention will be set forth.

The clamping of the core plate segment 13 to the support 11 of the carriage 7 is effected in such a manner that the center 13a of the core plate segment 13 coincides with the center of curvature 6a of the template 6 previously affixed to the carriage 7. In order to make possible a rapid and exact clamping, the individual clamping devices 12 may be adjustable for core plate segments of different dimensions. Subsequently, by turning the hand wheel 5, the clamping table is shifted by the threaded spindle 4 until the coinciding center points 6a and 13a assume the required distance from the stamping tool (not shown) affixed to the ram 3. In this manner, the diameter of the slot pitch circle is determined and the carriage 7 can be immobilized to prevent any unintended displacement thereof.

At the beginning of the slotting operation the carriage 7 is in the position illustrated in FIG. 3. The stamping machine then executes, in a continuous operation, the number of slotting steps necessary for the particular core plate segment 13. During this operation, the drive system formed of the two stepping motors 24 and 29 shifts the carriage 7 by the intermediary of the drive spindle 14 in a stepwise manner after each slotting step. The magnitude of the stepwise shift of the carriage 7 is determined as a function of the pitch mag nitude of the slots Nl-N7 to be cut in the core plate segment 13. With regard to numerical values, the magnitude of the stepwise shift is expressed in terms of the angular rotation about the centers 60 and 13a and equals the slot pitch. Since by the drive spindle 14 there is transmitted merely one component of the motion to be executed by the carriage 7, and thus the exact circular travelling path of the latter is solely determined by the template 6, it is necessary to continuously vary the magnitude of the feed executed by the drive spindle 14 for one and the same core plate segment 13.

For the purpose of maintaining the work period relating to slotting of one core plate segment 13 at a small value, the stamping machines usually operate with very high stroke frequencies. It follows that the period which is available for shifting the core plate segment 13 by one slot pitch by shifting the carriage 7 along the arcuate template 6 is correspondingly small. To accomplish an accurate carriage feed despite the small available time, the driving of the drive spindle 14 is effected by the two stepping motors 24 and 29. Each of these motors effects one predetermined part of the feed motion of the carriage 7. Thus, upon energization of the stepping motor 24, its rotary motion is directly transmitted to the drive spindle 14 which, accordingly, linearly shifts the carriage 7 (by virtue of the linear displacement of the nut 15 on and with respect to the spindle 14) by a distance that is the function of the thread pitch of the spindle 14. The stepping motor 29 may be simultaneously energized; its rotary motion is converted through the pinion 30 and the ring gear 17a into a longitudinal displacement of the setting socket 17. By virtue of the axial immobilization of the spindle 14 with respect to the socket 17, the latter and the spindle l4 shift axially as a unit. By affixing the stepping motors 24 and 29 to the support plate 26, it is ensured that during rotation of the socket 17 no relative motion will take place in the axial direction between the meshing pinion 30 and the ring gear 17a.

In order to ensure a high feeding speed of the carriage 7 while maintaining an accuracy in the pitch, the resolution capacity of the stepping motor 24 or the extent of motion caused by one step of the stepping motor 24 is maintained at a relatively large value, whereas that of the stepping motor 29 is maintained at a relatively small value. Thus, this result may be achieved, in two different, exemplary ways. According to one alternative, the stepping motors themselves are so selected that the angle of rotation of the output shaft of the stepping motor 24 during one step is greater than that of the stepping motor 29. Or, according to a second alternative, the angle of rotation during one step is identical in both stepping motors 24, 29, but along the force path between the second stepping motor 29 and the carriage 7 there is inserteda conventional step-down gear (constituted, for example, by meshing gears 17b and 30, having a predetermined step-down ratio). Thus, for example, assuming a required displacement of the carriage 7 of 8.86 mm, the stepping motor 24 causes by rotating the drive spindle l4 a shift of the nut 15 by a distance of 8.5 mm in 17 coarse steps of 0.5 mm each, while simultaneously, the stepping motor 29 effects the remaining longitudinal displacement of 0.36 mm of the nut 15 in eighteen steps of 0.02 mm each by rotating the socket 17 in the bearing sleeve and thus causing a purely axial shift of the drive spindle 14 (and the nut 15) through a distance of 0.36 mm.

As it may be seen from the abovegiven example, any required carriage feed may be effected with a small number of control commands of the stepping motors 24 and 29. In this manner it is possible not only to add the individual setting motions as outlined before. but also to subtract the same as it will be now described.

For such a case the stepping motor 14, assuming again a required displacement of 8.86 mm, executes eighteen steps of 0.5 mm each for advancing the carriage 7 by a distance of9 mm. Simultaneously, the stepping motor 29 is actuated for executing seven steps of 0.02 mm each in the rearward direction with respect to the longitudinal displacement of the socket 17.

Which of the two procedures (addition or subtraction) is adopted in each individual case depends on which procedure takes less time for setting the carriage 7. For the sake of completeness it is added that the setting motions of the stepping motors 24 and 29 may also be effected sequentially or, if sufficient for one particular operation, only a single stepping motor is activated. It is further noted that it is feasible to use more than two stepping motors in practicing the invention.

Since the resultant displacement of the drive spindle l4 varies from slot to slot for the purpose of ensuring a uniform displacement of the core plate segment 13, the number of the steps to be performed by the individual stepping motors 24 and 29 necessarily also changes. These steps thus are calculated in advance and are, by means of a programmer known by itself, fed to the stepping motors prior to each stepping operation.

It is further possible to provide that the stepping motor 24 executes, for one particular core plate segment, always a constant number of steps while the stepping motor 29 is programmed to execute the required number of steps in order to ensure an exact slot pitch or, as the case may be, the differing adjustments based on the circular path function.

it is further noted that the use of a ball-circulating spindle for the drive spindle 14 is advantageous to ensure essentially clearance-free displacements.

A significant advantage of the stamping machine according to the invention resides in the fact that by using a first stepping motor causing a relatively coarse displacement per step and a second stepping motor causing a relatively fine displacement per step, the setting speed for positioning the core plate segment can be increased without neglecting fine adjustment, and consequently, the stroke frequency of the die tool may be augmented.

It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

We claim:

1. A stamping machine for slotting annular segmentshaped plates, including a carriage for supporting the plate to be slotted; means for movably supporting the carriage; an arcuate template in engagement with the carriage for guiding the carriage in a circularly arcuate path, the improvement comprising:

a. a drive spindle having a driven side and a driving side;

b. means connecting said driving side of said spindle to said carriage for displacing said carriage upon 7 motion of said spindle by transmitting spindle movements to said carriage;

c. first and second stepping motors; and

(1. coupling means connecting said stepping motors to said driven side of said spindle for moving said spindle in response to the rotation of either one of said motors.

2. A stamping machine as defined in claim 1, including means for effecting carriage displacements of different magnitudes in response to one step of said first stepping motor and one step of said second stepping motor.

3. A stamping machine as defined in claim 2, wherein the displacement of said carriage caused by one step of said first stepping motor is greater than the displacement of said carriage caused by one step of said second stepping motor.

4. A stamping machine as defined in claim 1, further comprising e. first conversion means for converting a rotary motion of said drive spindle into a translational motion; said first conversion means forming part of said means connecting said driving side of said drive spindle to said carriage;

f. direct torque transmitting means directly connecting said first stepping motor with said driven side of said drive spindle for imparting a rotation to the latter; said direct torque transmitting means forming part of said coupling means;

g. second conversion means for converting a rotary motion of said second stepping motor into a translational motion; said second conversion means connecting said second stepping motor to said driven side of said drive spindle for imparting an axial shift to the latter; said second conversion means forming part of said coupling means.

5. A stamping machine as defined in claim 4, said second conversion means including a setting socket through which extends a Zone of said driven side of said drive spindle, said setting socket having external threads; and means in said setting socket for preventing an axial displacement of said drive spindle with respect to said setting socket.

6. A stamping machine as defined in claim 5, further comprising a bearing sleeve surrounding said setting socket and having internal threads in engagement with said external threads of said setting socket; a bearing plate fixedly attached to said bearing sleeve; a displaceable clamping table on which said carriage is movably mounted; and means securing said bearing plate to said clamping table for rotary movement of said bearing plate about an axis perpendicular to the longitudinal axis of said drive spindle.

7. A stamping machine as defined in claim 6, further comprising a support plate carrying said first stepping motor; and means for securing said support plate to said bearing plate for relative movement between said support plate and said bearing plate.

8. A stamping machine as defined in claim 7, wherein said first stepping motor is carried by said support plate.

9. A stamping machine as defined in claim 8, wherein said second stepping motor is carried by said support plate.

10. A stamping machine as defined in claim 7, wherein said means for securing said support plate to said bearing plate includes at least one bolt affixed to said support plate and extending parallel to said drive spindle in a direction towards said bearing plate; and guide means in said bearing plate for slidably receiving said bolt.

11. A stamping machine as defined in claim 5, further comprising means connecting said second stepping motor with said setting socket for rotating said setting socket by said second stepping motor.

12. A stamping machine as defined in claim 11, wherein said means connecting said second stepping motor with said setting socket includes a ring gear affixed to said setting socket and a pinion affixed to an output shaft of said second stepping motor, said ring gear and said pinion being in a meshing relationship with one another.

13. A stamping machine as defined in claim 1, wherein said drive spindle is a ball-circulating spindle.

14. A stamping machine as defined in claim 1, wherein said means connecting said driving side of said spindle to said carriage includes a ball-circulating nut affixed to said carriage non-rotatably with respect to said drive spindle; said drive spindle extending through said nut and being operatively connected thereto for causing a shift of said nut in response to the motion of said drive spindle.

15. A stamping machine as defined in claim 14, including means securing said nut to said carriage for a rotational movement of said nut about an axis perpendicular to the longitudinal axis of said drive spindle.

16. A stamping machine as defined in claim 1, including a plurality of rollers secured to said carriage, said rollers being in engagement with arcuate, parallel, inner and outer faces of said arcuate template for guiding said carriage along said arcuate template.

17. A stamping machine as defined in claim 16, wherein each roller cooperating with one of said faces of said arcuate template has a fixed support in said carriage; and each roller cooperating with the other of said faces has an adjustable support in said carriage for urging each roller cooperating with said other of said faces against the latter with a bias.

18. A stamping machine as defined in claim 17, wherein said adjustable support comprises a pin eccentric with respect to the rotary axis of the roller it supports.

19. A stamping machine as defined in claim 1, further including a ram adapted to carry a slotting tool; a clamping table carrying said carriage and said template; and means for displacing said clamping table towards and away from said ram.

20. A stamping machine as defined in claim 1, wherein at least one of said stepping motors is programcontrolled. 

1. A stamping machine for slotting annular segment-shaped plates, including a carriage for supporting the plate to be slotted; means for movably supporting the carriage; an arcuate template in engagement with the carriage for guiding the carriage in a circularly arcuate path, the improvement comprising: a. a drive spindle having a driven side and a driving side; b. means connecting said driving side of said spindle to said carriage for displacing said carriage upon motion of said spindle by transmitting spindle movements to said carriage; c. first and second stepping motors; and d. coupling means connecting said stepping motors to said driven side of said spindle for moving said spindle in response to the rotation of either one of said motors.
 2. A stamping machine as defined in claim 1, including means for effecting carriage displacements of different magnitudes in response to one step of said first stepping motor and one step of said second stepping motor.
 3. A stamping machine as defined in claim 2, wherein the displacement of said carriage caused by one step of said first stepping motor is greater than the displacement of said carriage caused by one step of said second stepping motor.
 4. A stamping machine as defined in claim 1, further comprising e. first conversion means for converting a rotary motion of said drive spindle into a translational motion; said first conversion means forming part of said means connecting said driving side of said drive spindle to said carriage; f. direct torque transmitting means directly connecting said first stepping motor with said driven side of said drive spindle for imparting a rotation to the latter; said direct torque transmitting means forming part of said coupling means; g. second conversion means for converting a rotary motion of said second stepping motor into a translational motion; said second conversion means connecting said second stepping motor to said driven side of said drive spindle for imparting an axial shift to the latter; said second conversion means forming part of said coupling means.
 5. A stamping machine as defined in claim 4, said second conversion means including a setting socket through which extends a zone of said driven side of said drive spindle, said setting socket having external threads; and means in said setting socket for preventing an axial displacement of said drive spindle with respect to said setting socket.
 6. A stamping machine as defined in claim 5, further comprising a bearing sleeve surrounding said setting socket and having internal threads in engagement with said external threads of said setting socket; a bearing plate fixedly attached to said bearing sleeve; a displaceable clamping table on which said carriage is movably mounted; and means securing said bearing plate to said clamping table for rotary movement of said bearing plate about an axis perpendicular to the longituDinal axis of said drive spindle.
 7. A stamping machine as defined in claim 6, further comprising a support plate carrying said first stepping motor; and means for securing said support plate to said bearing plate for relative movement between said support plate and said bearing plate.
 8. A stamping machine as defined in claim 7, wherein said first stepping motor is carried by said support plate.
 9. A stamping machine as defined in claim 8, wherein said second stepping motor is carried by said support plate.
 10. A stamping machine as defined in claim 7, wherein said means for securing said support plate to said bearing plate includes at least one bolt affixed to said support plate and extending parallel to said drive spindle in a direction towards said bearing plate; and guide means in said bearing plate for slidably receiving said bolt.
 11. A stamping machine as defined in claim 5, further comprising means connecting said second stepping motor with said setting socket for rotating said setting socket by said second stepping motor.
 12. A stamping machine as defined in claim 11, wherein said means connecting said second stepping motor with said setting socket includes a ring gear affixed to said setting socket and a pinion affixed to an output shaft of said second stepping motor, said ring gear and said pinion being in a meshing relationship with one another.
 13. A stamping machine as defined in claim 1, wherein said drive spindle is a ball-circulating spindle.
 14. A stamping machine as defined in claim 1, wherein said means connecting said driving side of said spindle to said carriage includes a ball-circulating nut affixed to said carriage non-rotatably with respect to said drive spindle; said drive spindle extending through said nut and being operatively connected thereto for causing a shift of said nut in response to the motion of said drive spindle.
 15. A stamping machine as defined in claim 14, including means securing said nut to said carriage for a rotational movement of said nut about an axis perpendicular to the longitudinal axis of said drive spindle.
 16. A stamping machine as defined in claim 1, including a plurality of rollers secured to said carriage, said rollers being in engagement with arcuate, parallel, inner and outer faces of said arcuate template for guiding said carriage along said arcuate template.
 17. A stamping machine as defined in claim 16, wherein each roller cooperating with one of said faces of said arcuate template has a fixed support in said carriage; and each roller cooperating with the other of said faces has an adjustable support in said carriage for urging each roller cooperating with said other of said faces against the latter with a bias.
 18. A stamping machine as defined in claim 17, wherein said adjustable support comprises a pin eccentric with respect to the rotary axis of the roller it supports.
 19. A stamping machine as defined in claim 1, further including a ram adapted to carry a slotting tool; a clamping table carrying said carriage and said template; and means for displacing said clamping table towards and away from said ram.
 20. A stamping machine as defined in claim 1, wherein at least one of said stepping motors is program-controlled. 